(1) Field of the Invention
The present invention relates to improving the performance and reliability of valves of the type which employ a plurality of movable, coaxially arranged annular plates. More specifically, this invention is directed to plate valves of the type particularly well suited for use as one-way flow control devices at the intakes to and discharges from reciprocating compressors. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
(2) Description of the Prior Art
Check or one-way flow control valves employing annular plates as the moving elements or valve members are well known in the art. A plate valve characterized by significantly enhanced efficiency, when compared to prior art devices of similar character, is disclosed in co-pending application Ser. No. 837,408 which is assigned to the assignee of the present invention. Another example of a prior art plate valve of the type to which the present invention is directed may be found in U.S. Pat. No. 3,656,500. Plate valves are employed in both the inlets to and discharge lines from reciprocating compressors. In a typical reciprocating type compressor installation, there may be from two to twenty valves per cylinder and thus a single compressor may have in excess of one hundred valves associated therewith. A failure of any one valve will disable the entire compressor. Accordingly, reliability is a prime consideration in the design of a plate valve.
The typical prior art plate valve has a seat member and a guard member which cooperate to define the valve housing. The seat member is provided with a plurality of arcuately shaped passages therethrough and these passages are arranged in concentric circles to thereby effectively define a plurality of annular passages which communicate with the valve chamber or chambers. The guard member, which is shaped to form the valve chamber, is also provided with passages which effectively define a plurality of concentric ports or passages. The passages in the guard member are radially staggered with respect to the passages in the seat member. The guard member is also provided with recesses which receive biasing springs. The annular plates or valve members are located in the valve chamber intermediate the seat and guard members and have a flat surface with a width exceeding the width of the inwardly disposed ends of the passages in the seat member. Posts, typically extending from the guard member, constrain the annular plates to movement only toward and away from the inwardly disposed ends of the passages in the seat member which they cover in the closed position. The annular valve plates are resiliently biased, by means of the aforementioned springs located in the recesses in the guard member, against the seat whereby the valve will normally be closed. When the forces on the plates resulting from the applied pressure exceed the spring bias, the plates will move away from the seat and fluid will flow through the valve. In view of the radial offset of the passages in the seat member with respect to those in the guard member, fluid flowing through the valve will undergo a change in direction. The valve of co-pending application Ser. No. 837,408 constitutes a significant step forward in the art by virtue of enhancing valve efficiency be minimizing pressure losses. Those unique characteristics of the valve of application Ser. No. 837,408 which contribute to the minimizing of pressure losses are employed in the valve of the present invention and thus the disclosure of application Ser. No. 837,408 is hereby incorporated herein by reference.
For the reasons briefly discussed above, there is a long standing desire in the art to further enhance the reliability of a plate valve, including the valve of aforementioned application Ser. No. 837,408, without sacrificing overall system efficiency by increasing the pressure losses which may be attributed to the valve. Further, it has also been desired to reduce manufacturing costs, and particularly expensive machine steps, without adversely affecting either pressure drop or valve reliability.